A Mechanoresponsive Fluorescent Mg‐Zn Bimetallic MOF with Luminescent Sensing Properties

• Published in: ChemistrySelect (Weinheim) 2018-05, Vol.3 (17), p.4884-4888
• Main Authors: Wu, Zhao‐Feng, Huang, Xiao‐Ying
• Format: Article
• Language: English
• Subjects: fluorescent detection; heterometallic MOF; magnesium; mechanoresponsive fluorescence; zinc
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.201800580

Presented here are the synthesis, crystal structure and fluorescent properties of a Mg−Zn bimetallic metal organic framework (MOF), namely [MgZn(1,4‐NDC)2(DMF)2 (1, 1,4‐NDCH2=1,4‐naphthalene dicarboxylic acid). Compound 1 possesses a three‐dimensional (3D) structure constructed by the 1,4‐NDC linkers bridging the infinite one dimensional (1D) chain of [–Mg–(COO)2–Zn–(COO)2–]n. Photoluminescence studies indicated that 1 shows a grinding mechanoresponsive fluorescence changing from green to blue emission. Notably, thus far there is no investigation on the mechanoresponsive fluorescent properties of Mg‐based heterometallic MOF. Moreover, the blue emitting powdered sample could not only act as an effective fluorescence sensor for Fe3+/Cu2+/CrO42− ions, but also exhibit sensitive fluorescent detection for the low‐concentration CS2 and nitro‐containing compounds. This work may provide a certain guiding significance for exploring functional heterometallic fluorescent MOFs based on the environmentally friendly and abundant Mg2+. A 3D Mg−Zn heterometallic MOF of [MgZn(1,4‐NDC)2(DMF)2 (1, 1,4‐NDCH2=1,4‐naphthalene dicarboxylic acid) has been synthesized and characterized. Compound 1 represents the first Mg‐based bimetallic MOF with mechanoresponsive fluorescence. After being ground, the powdered sample (1′) emitted blue fluorescence that was obviously different from the green emission of the pristine crystals of 1. In addition, sample 1′ demonstrated fluorescence sensing towards Fe3+, Cu2+, CrO42−, CS2 and nitro‐explosives with low concentrations.